A home battery allows homes to store energy when you are either producing more solar power than you’re using, or store energy from the grid if the current price is low.
Home Assistant allows you to track how much energy flows from/to your battery.
Home Assistant will need to know the amount of energy flowing from/to your batteries. This data can be tracked in various ways.
Some battery vendors have an API to integrate the data into your Home Assistant instance. An example is Tesla Powerwall.
Current transformer (CT) clamp sensors measure your energy usage by looking at the current passing through an electrical wire. This makes it possible to calculate the energy usage. In Home Assistant we have support for off-the-shelf CT clamp sensors or you can build your own.
- The off-the-shelf solution that we advise is the Shelly EM. The device has a local API, updates are pushed to Home Assistant and it has a high quality integration.
- You can build your own using ESPHome’s CT Clamp Current sensor or energy meter sensors like the ATM90E32. For the DIY route, check out this video by digiblur to get started.
Attention! Installing CT clamp sensor devices requires opening your electrical cabinet. This work should be done by someone familiar with electrical wiring and may require a licensed professional in some regions. Your qualified installer will know how to do this.
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